Mongo

Something tells me that any new design intakes will require a revised cam profile in order to maximize on gains. I am tempted to see something very similar to an LS (or even a Cayenne) manifold on these cars. There is gain there and the intake is not exactly a modern design.

Imo000

Use the search function and look for Greg's posts from a few years ago.

Mongo

I am familiar with his intake setup. Production would be nice but sadly the market demand is low.

Cost would be high I am sure, but how about going polymer???? Maybe that is a question for Greg to answer if he has not done so already (either on this thread or his old one). I am on a droid right now and it is slow. Search is not my friend today.

James Bailey

OK so no changes simply a aftermarket rising rate fuel pressure regulator and you get from 55hp to 123 hp at the rear wheels ?? Where can we buy one ???? Do you see where you have credibility issues ?
You say above stock S-4 400hp with "proper" intake then later say well at least 50hp it is like you contradict yourself as much as you argue with others.
Also pretty clear that you do not realize that a carburetor on a tunnel ram means a complete intake system and is NOT like just a throttle body but it matters little. However read the entire Hotrod link on the LS engine and you really would learn a lot. Like how they think $1,000 for an intake is too expensive. How the carbs made nearly as much horsepower. How some intakes lost power at lower RPM....
But mostly how you as an individual would learn more by reading than by writing....probably have more friends too.
You may now have the LAST words on this "debate" as I no longer find it amusing.

James Bailey

For anyone else wondering why a 4.3 v-8 Vantage makes more power...11.3 compression , vario cam and more lift, dry sump, sequential injection , and most important it peaks at 7,000 RPM vs the 6,000 rpm or so of a 928. But other than that just like a 928

Imo000

Cheburator

11.3:1 - difficult to argue with against a 9.5:1 S4 and even the GTS and the S2 are only 10.4:1

Vario cam - nothing there, just makes it more driveable lower down, the 5.0 will have more torque by default

More lift - difficult to argue with, Colin's cams address the issue for not a lot and are a simple drop in. PorKen's tool make timing them easy

Sequential injection - better fuel economy, but almost nothing for maximum power

7000 rpm - even a stock street 928 will happily spin to 7000, but if it ain't breathing and "exhaling" well, not much happens. If you are to change the intake, you will make it breathe better, the tubular stock exhaust is ok-ish, ergo, you will make more power higher up. Should you change the exhaust you will make even more.

A bone stock GTS with GT cams, 928 Intl headers, X-pipe and custom 2.5" dual exhaust just dynoed at 308rwhp on a real dyno.

Imo000

Colin's cams require the springs to be changed and then the spring compression dimensions have to be measured. Not exactly what I would call a drop in.

Mongo

I'm just curious, what are the injector flow rates for that Aston Martin? 928s being stock at 19lbs/hr after 1987 are maxed out. Ken's 24lbs and chip clearly wake the car up, but who here has actually fudged around with even bigger injectors on an NA application? Why not 30lbs, **** why not 36-40lbs?

I've been hanging out in the LS1Tech forums lately, and those guys just throw gas at everything, regardless of forced induction or naturally aspirated and keep making power. I'm sorry, but a new intake HAS to happen for these cars to make more power. If I have to grovel to the wife for the new product, I will.

mark kibort

THANK YOU!! yes, those are my points too. that GTS is anemic if it only got 308 with all that stuff . i did a REAL dyno and several "not real "dynos" anythig that could measure rear wheel power and ive used it. and always got between 317 and 322rwhp with the stock 5 liter with GTcams.. i think the main issue here for the GTS is that its using the GTS cams.

yes, vario cam.... no factor here. thats only down low.. who cares.
10:1 is plenty of compression. 11.3:1 is responsible for less than a 5% gain
sequential injection?? so what.. means litterally nothing.. agreed

it needs an intake.. I dont know why anyone would fight this. tell jim to look at the specs for the stock boss 302 mustang!!! 430rhwp with nothing more than chip changes, headers and ECU flash

Jim..jim jim!.... Reallly? why are you fighting this. vario cam doesnt do anything up top, 11.3 vs 10:1 is little gains for that alone, more lift? how much? if so, noted but duration is close to GT cams as they are today.
dry sump?? that means nothing either... Joes car always made more HP than marks and he was wetsump... drysump doesnt gurantee any power at all,
and now you say, "MOST IMPORTANT, RPM OF 7000"?? really?????? ugg the S4 revs up to 6600rpm and the GT up to 6800rpm. there is NOTHING in the advantage here. again, more reasons for gettting the intake!!!

so, please find something that really stands out over the 928.... OH JIM< did you notice that the vantage is only a 4.3LITER!!!!! 4.3 LITERs!!!!!!!!
Its all intake....... please believe me!!!

Ive already prved you can run a 5 liter with stock injectors up to 335rwhp. .. all you need to do is pump up the pressure with a RRFR OR you can chip it , but i think the higher pressure is a better way in someways for better atomization.

the reason you dont want to use 30lb'ers, on the 928, is that the fuel pressure would have to be pretty low and is the problem i have with even the stroker. now, if you can change duration with the chip, its better off, which would be better for me, but i think with the 5 liter, the 24lbers would be optimal for some mods geting near the 350rwhp range , and the strokers would be better here too, or with chip mods to get the injector duration down and the fuel pressure in the optimal zone (near 50psi)

(EDIT: below )
below are HP curves from the vantage V8 with 4.3 liter engine notice that the curve is pretty nice..

bigger is better! we need to learn from this!! RPM is not that high on the test, though the redline is really in the 7800rpm range actually!

first curve is back box upgrade which is a muffler change only and is mostly stock!!
second curve is with power upgrade from aston martin.. ( power upgrade package which is new air box plennum and air filter) picture below!

Mongo

I don't understand how the fuel pressure would be an issue with the flow rate in this application. Can you please clarify?

mark kibort

Those are 31mm and 35mm valves on the AMV8 too. smaller than the S4 (S4 VALVES 37mm and 33mm) !!!!!!
with no other changes the intake mod below, gives the power of the V8 vantage 4.3 as much as the v8 vantage 4.7L.... thats the equivilant of 400cc.. kind of like the S4 to the GTS, just to change an already awesome intake plennum to a little larger one.
Just imagine what would happen to the S4 with a PROPER air box plennum!!!!!!
im predicting 300-320rwhp on any S4 for just slapping on a proper intake manifold.

mark kibort

it has 11mm lift, which is very close.... a base grind on the GT cams can get this.
thats on the race Vantage 4.7 V8.. i think the 4.3 has the 10mm lift , like the GT cams.

i still dont understand why the peak hp points have anything to do with anything arguable? maybe that the intake wouldnt be as effective? hardly a theory here, considering that the engine we are talking about has 5 liters vs the small 4.3 liter of the vantage.
trust me, and you know this deep down... a nice intake will make the S4 5 liter come alive!!

Mongo

Of course, this has been proven with Greg's intake and those carbon fiber intakes a while back. It's just no one has jumped on the bandwagon of mass-production due to cost. I assume a polymer intake is staggeringly expensive to produce too due to the investment into injection molding and new templates.

Cheburator

I respectfully disagree. Colin's cams work with stock valve springs pretty well. I have them in my race motor, which has now been flogged mercilessly for about 20hrs, redline of 7000rpm, 12:1 compression on non stock JE Pistons. I don't short shift it at all. Never.

You would think that I would have noticed by now if there was valve float?

P.S. The Pistons have been notched for the 968 intake valves, but even with the crescents, they are still 12:1. Yet again, if there was contact due to inadequate springs, given that the car is really driven by an animal (my co-driver) only on track, I would have known